(1) Field of the Invention
This invention relates to a tool for removing a threaded fastener having a damaged or multilated wrench receiving recess therein, and more particularly relates to a tool for removing cap screws, set screws, and other threaded devices having a damaged or mutilated, hexagonally-shaped, torque receiving recess therein.
(2) Description of the Prior Art
Various devices have been heretofore developed for effecting removal of threaded fasteners from a part or member with which the fastener was engaged, either because a conventional tool could not apply sufficient torque to the fastener to effect removal thereof or because the head of the fastener was damaged to the extent that a conventional tool could not properly engage the fastener. Examples of some tools which have been developed for effecting the removal of screws having damaged heads are disclosed in the Hilsinger U.S. Pat. No. 2,750,821 and Cummaro U.S. Pat. No. 2,815,054 patents. These devices were, however, complex in construction and difficult to use.
Devices have also been developed for removing broken or damaged studs. Examples of such devices are disclosed in the Murphree U.S. Pat. No. 1,547,944 and Ferrell U.S. Pat. No. 1,604,032 patents. However, the latter two devices required drilling of a hole in the damaged stud before the removing tool could be engaged therewith to effect unthreading of the stud.
The problem of removing cap screws having hexagonal sockets in the head thereof has been particularly difficult whenever the socket in the head became damaged or mutilated to the extent that an appropriately sized Allen wrench, or other torque applying tool, could not properly engage and transmit torque to the screw. A screw extracting tool ostensibly capable of removing cap screws having hexagonally-shaped recesses in the heads thereof is disclosed in the Joyce U.S. Pat. No. 2,923,335. However, due to the high amount of torque required to effect disengagement of cap screws or set screws which have been overtightened, rusted, or otherwise abnormally engaged with an associated part, the extracting tool disclosed in the Joyce U.S. Pat. No. 2,923,335, could not be relied upon to apply the degree of torque necessary to effect removal of the screw.